Mu‘awiyah ibn ‘Ammar narrated from Najiyyah, who said:
I said to Abu Ja‘far عليه السلام, peace be upon him: “The time for prayer comes upon me, should I begin with the supererogatory prayer?” Imam عليه السلام said: “No, begin with the obligatory prayer and make up the supererogatory prayer afterward.”
Ali Akbar al-Ghaffari
Tahdhīb al-Aḥkām fī Sharḥ al-Muqniʿah, vol. 2, p. 264